1. Field of the Invention
The present invention relates to heat dissipating technology for electric motors.
2. Description of the Related Art
To maintain the performance and prolong the lifecycle of an electric motor, the heat generated when the electric motor is operating has to be appropriately removed. The prior art usually uses a cooling pipe and the working fluid flowing through the cooling pipe to remove the heat generated from the electric motor.
FIG. 1A is a structural view of the cooling pipe in the prior art. The cooling jacket 100 can be used to remove heat from the electric motor. The electric motor is not shown in this Figure for simplicity (where the arrow represents the axis direction of the electric motor). As shown in FIG. 1, the pipe in the cooling jacket 100 is substantially in a wave shape, covering the surface of the electric motor. The working fluid is injected into the cooling jacket 100 through the working fluid inlet 110, changes its flow direction several times, and is finally expelled from the working fluid outlet 120. The turning portion between tubes has a different length L (as labeled in this Figure) in different designs. Generally, the shorter the length L of the turning portion, the higher the manufacturing cost; while the longer the length L of the operating portion, the more the heat concentrates there. Some designs attempt to improve the heat dissipating ability by enlarging the pipe diameter and increasing the quantity of the working fluid, but usually achieve limited success. FIG. 1B shows a corner of the pipe in the prior art which has an enlarged diameter. In FIG. 1B, when the working fluid flows into the pipe, the inertia of the working fluid tends to make the stream A stop flowing or flow in a reversed direction with respect to the stream B, thus causing heat to concentrate where the stream A is.
Therefore, a new cooling jacket for cooling the electric motor which overcomes said defects is needed.